The present invention relates to a recycling automatic document feeder (RADF) for use with a copier or similar image recording apparatus and, more particularly, to a document feeding method practicable with an RADF.
An automatic document feeder (ADF) capable of automatically feeding documents one by one to a recording position of a copier or similar image recording apparatus is extensively used today. The ADF is often implemented as an RADF which automatically feeds documents stacked on a table thereof one by one to an exposing position on a glass platen of a copier and returns each of them after they have undergone illumination to the table, i.e., the top of the stack remaining on the table. It is a common practice with the RADF to use a single drive source in driving two independent means, i.e., means for pulling out the documents from the stack one at a time and means for transporting the document to the glass platen of the copier. This is to promote the miniaturization of the RADF. A document feeding method practicable with such an RADF returns a document having been illuminated at the exposing position to the table at the same time as it feeds the next document from the table.
The problem with the conventional automatic document feeding method is that two or more documents cannot be fed by a single document feeding operation and, therefore, the interval between the successive documents is relatively long, resulting in low transport efficiency. Such a method, therefore, obstructs an increase in the operating speed of the RADF. To implement a high-speed RADF, the timings for feeding and returning a document may be changed on the basis of the size of the document so as to reduce the interval between successive documents. Further, the last document to be returned may be discharged to the table almost simultaneously with the immediately preceding document. These schemes, however, bring about another problem that since the interval between the last and immediately preceding documents is short, the last document is apt to contact the preceding document to be thereby bent or caused to get under the immediately preceding document.